Automated specimen testing devices are widely used, for example, to test biological samples such as blood for medical purposes. In many such devices, efficient and cost effective testing requires that multiple specimen containers (e.g., test tubes) often be handled together for individual testing of the various specimens in the various containers.
In such automated devices, a plurality of containers are often placed in an array on an input deck. In some devices, the containers are themselves transported from the input deck to another part of the device for testing or other processing. In other devices, the containers may be positioned placed on the deck and then parts of the specimens may be automatically transported from the containers to other areas or containers of the device, for example by drawings parts of the specimens out of the containers by use of pipettes inserted into the containers and then transporting the pipettes to the other area or containers where the pipettes discharge the drawn specimens.
One such prior art structure which has allowed the specimen containers to be placed on the input deck with the specimens drawn out by pipettes is illustrated in FIG. 1. Specifically, a closed housing 10 secured to the deck 12 includes a pair of side walls 14 supporting a cover member 16 with an array of holes 18 therein. A plurality of open topped racks 20 are suitably secured to the deck 12, each rack 20 being longitudinal and defining a row of cylindrical openings 22 for supporting a row of containers or tubes 24 having specimens therein for testing or otherwise processing on the device. Each rack 20 may be secured in a position on the deck 12 in any suitable manner, such as a dovetailed groove 26 on the bottom which cooperates with a similar dovetailed projection from the deck 12, whereby a user can grasp a rack 20 by its projecting grip 28 on the end and slide the rack 20 into a position under the housing 10. Pipettes are thereafter moved down through the holes 18 in the cover member 16 and into the containers 24 to draw out desired amounts of the specimens contained therein.
In order to protect against contamination, the containers 24 may include covers over their top with pierceable membranes (e.g., elastic membranes) so that the pipettes may pierce the membranes to enter the containers 24 for access to the specimens contained therein, with the membranes substantially closing after the pipettes are removed, thereby both protecting the remaining specimens against external contamination and ensuring that nothing from the containers 24 escape to contaminate other specimens. The cover member 16 of the housing 12 helps to ensure that when the pipettes are retracted back up after accessing the specimens, the containers 24 will be retained in their rack 20 without being pulled up with the pipettes (if the pipettes get stuck in the membranes).
However, the above described structure has a plurality of disadvantages. If a rack 20 is not properly located on the deck 12, it may not be properly aligned with the array of openings 18. Thus, a pipette which is moved down through specific openings may not be aligned properly with the container 24 opening and could instead collide with and damage the container 24. Further, it should be appreciated that the housing 10 effectively restricts or even blocks access to many containers 24, particularly those containers 24 located in the middle of the array. Such access may be required, for example, to optically read labels on the containers to identify each container 24 having specific specimens. Of course, automatic operation requires that the device be able to identify containers so that the device may automatically conduct appropriate tests on those specific specimens requiring such tests.
Another prior art structure which has been used for similar purposes has included a rack which has an array of multiple rows (for example, twelve rows of eight), with corner posts on which a cover member may be removably mounted. With this rack, a plurality of containers may be placed in the array of openings in the rack and then the cover member is secured over the containers by bolt and nut or screw type connections to the corner posts at the corners of the cover member.
While this rack will reasonably reliably ensure that the array of openings in the cover member will be aligned with the containers therebeneath, it will particularly restrict or even block access to many containers (particularly those containers 24 located in the middle of the array) such as required to optically read labels on the containers. Further, it occupies the entire array on the device deck, and thus may either require that some tests be undesirably delayed (waiting on additional specimens requiring testing to fill up the rack before placing the rack on the device deck) or require inefficient use of the device (by mounting a rack occupying an entire array of container positions with only a few specimen containing containers). Moreover, if it is desired to add or remove any container after the rack is mounted on the device deck, it is required that the cover member be removed and, during that time, pipettes may not be used to get specimens from any containers in the rack as none of the containers will be covered so as to prevent them from sticking on the pipettes and being undesirably carried from the rack when the pipettes retract. Of course, securing the cover member over the rack, and removing the cover member from the rack, itself takes time which can result in inefficient use of the device which may have to sit idle waiting for that to be completed before starting the pipetting and/or container identification processes.
The present invention is directed toward overcoming one or more of the problems set forth above.